A novel sulfite coupling electro-fenton reactions with ferrous sulfide cathode for anthracene degradation

Abstract In the present study, pyrite modified carbon felt (FeS2/CF) was used as cathode in electrochemical advanced oxidation for the first time. The FeS2/CF cathode can provide Fe(II) and oxysulfide continuously through this sulfite coupling heterogeneous electro-Fenton (HEF) process without leaching of iron, which further induced the formation of SO4∙− and OH. The cumulative concentration of OH was 26.83 μM after 20 min at the current density of 10 mA cm−2, which was about twice higher than that in the electrochemical system with CF only. The estimated steady-state concentrations of SO4∙− and OH in this HEF system can be as high as 7.37 × 10−4 μM and 2.44 × 10−4 μM, respectively. This electrochemical system with FeS2/CF cathode shows remarkable efficiency (>80%) for anthracene (ANT) degradation in a wide pH of 3–9, and can be used for at least six times. The major degradation products of ANT were identified as anthraquinone and other four hydroxylated products. The study provides a novel aspect of FeS2 in HEF processes, and is expected to be an efficient technology in water treatment processes.